/*
    #include <GL/glut.h>
    #define window_width  640
    #define window_height 480
    // Main loop
    void main_loop_function() {
        // Z angle
        static float angle;
        // Clear color (screen)
        // And depth (used internally to block obstructed objects)
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        // Load identity matrix
        glLoadIdentity();
        // Multiply in translation matrix
        glTranslatef(0, 0, -10);
        // Multiply in rotation matrix
        glRotatef(angle, 0, 0, 1);
        // Render colored quad
        glBegin(GL_QUADS);
        glColor3ub(255, 000, 000);
        glVertex2f(-1, 1);
        glColor3ub(000, 255, 000);
        glVertex2f(1, 1);
        glColor3ub(000, 000, 255);
        glVertex2f(1, -1);
        glColor3ub(255, 255, 000);
        glVertex2f(-1, -1);
        glEnd();
        // Swap buffers (color buffers, makes previous render visible)
        glutSwapBuffers();
        // Increase angle to rotate
        angle += 0.25;
    }
    // Initialze OpenGL perspective matrix
    void GL_Setup(int width, int height) {
        glViewport(0, 0, width, height);
        glMatrixMode(GL_PROJECTION);
        glEnable(GL_DEPTH_TEST);
        gluPerspective(45, (float) width / height, .1, 100);
        glMatrixMode(GL_MODELVIEW);
    }
    // Initialize GLUT and start main loop
    int main(int argc, char** argv) {
        glutInit(&argc, argv);
        glutInitWindowSize(window_width, window_height);
        glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
        glutCreateWindow("GLUT Example!!!");
        glutIdleFunc(main_loop_function);
        GL_Setup(window_width, window_height);
        glutMainLoop();
    }

*/
